"Rest" periods are a useless concept. What is needed is an acceptance of the way the human body works, and tailoring the way a roster is laid out so that people are not asked to try to sleep in the middle of their body clock's day, or ask them to perform to the best of their ability when their system is convinced that it's 04:00.
Aircrew will always be awake a few hours before due to report for an early if their roster does not allow them to adjust their systems appropriately. If they are unable to sleep when they need to, to throw accusations of irresponsibility at them of misuse of a rest period is to blind oneself to the responsibility that the roster organiser has.